Manifold imaging method

ABSTRACT

AN IMAGING SYSTEM USING A MANIFOLD SET INCLUDING A SOLID LAYER WHICH MAY BE ACTIVATED BY HEAT IS DESCRIBED. THE SET TYPICALLY CONSISTS OF A DONOR SHEET, A COHESIVELY WEAK PHOTOSENSITIVE LAYER, A LOW MELTING LAYER AND A RECEIVING SHEET. THE SET IS HEATED ABOVE THE MELTING TEMPERATURE OF THE LOW MELTING LAYER, AN ELECTROSTATIC LATENT IMAGE IS FORMED IN THE PHOTOSENSITIVE LAYER AND THE SHEETS ARE SEPARATED, FORMING POSITIVE AND NEGATIVE IMAGES ON THE TWO SHEETS CONFORMING TO THE LATENT IMAGE.

United States Patent ()lfice 3,598,581 Patented Aug. 10, 1971 3,598,581 MANIFOLD IMAGING METHOD Gedeminas J. Reinis, Rochester, N.Y., assignor to Xerox Corporation, Rochester, N.Y. Filed Apr. 3, 1967, Ser. No. 628,028 Int. Cl. G03g 5/00, 13/00 US. Cl. 96-15 7 Claims ABSTRACT OF THE DISCLOSURE The present invention relates in general to imaging systems and, more specifically, to an improved system for the formation of high gamma images by layer transfer in image configuration.

Recently, there has been developed an imaging system in which portions of a cohesively weak photoresponsive imaging material are traansferred from a donor sheet to a receiving sheet in image configuration. This system is described in detail and claimed in copending application 452,641, filed May 3, 1965, now abandoned. In this system, a layer of a cohesively weak photoresponsive imaging material is coated onto a substrate. These two layers are referred to as the donor. Generally, it is necessary to activate the photoresponsive layer by treating it with a swelling agent or a partial solvent for the material. The activating step serves the dual function of making the top surface of the imaging layer slightly tacky and, at the same time, weakening it structurally so that it can be fractured more easily along a sharp line which defines the image to be reproduced. Once the imaging layer is activated, a receiver sheet is laid down over its surface. A potential is then applied across the manifold set while it is exposed to a pattern of lightand-shadow representative of the image to be reproduced. Upon separation of the donor substrate from the receiver sheet, the imaging layer fractures along the lines defined by the boundaries of the pattern of light-andshadow to which it has been exposed with part of this layer being transferred to the receiver sheet while the rernainder is retained on the donor substrate resulting in a positive image on one while a negative image is produced on the other. This imaging system is capable of producing images of high contrast and of good quality. However, the step of activating the donor layer with a swelling agent or solvent makes the process undesirably complex. It would be desirable to be able to ship and store the donor layer with the receiver sheet in place and to then image without having to perform the steps of separating the sheets, introducing a solvent onto the donor and replacing the receiver sheet. In a commercial embodiment, the inclusion of a liquid is undesirable. Fumes or vapors from a volatile solvent may be objectionable to users of the system. Also, obtaining uniform application of the activating fluid is difficult. Thus, there is a continuing need for improvements in such imaging systems to simplify the process, insure uniformity of image formation and to eliminate wet processing steps.

It is, therefore, an object of this invention to provide an imaging system overcoming the above-noted disadvantages.

It is another object of this invention to provide a dry high gamma imaging system.

It is a further object of this invention to provide an improved high contrast photographic strip-out process.

A further object of this invention to provide an imaging process of the lowest possible order of complexity.

It is also an object of this invention to provide an improved imaging process which simultaneously forms a positive and a negative.

The above objects and others are accomplished, fundamentally, by providing a manifold set comprising a substrate, coated thereover an imaging layer comprising a layer of a cohesively weak photoresponsive imaging material overcoated with an activating layer and in place thereover, a receiving sheet. If desired, the activating layer may be precoated directly on the receiving sheet. The photoresponsive layer and activating layer combination has a greater initial adhesion to the substrate than to the receiving sheet. The substrate and/or the receiving sheet is at least partially transparent. A potential is applied across the imaging layer while an image is projecte d onto the layer. Either just before or during the imaging operation, the activating layer is heated to render the imaging layer cohesively weak. The activating layer comprises a material which melts at a lower temperature than the photoresponsive layer upon heating and at least partially dissolves the body of the imaging layer, thus rendering it weak structurally so that it can be fractured more easily along a sharp line which defines the image to be reproduced and makes the top surface of the imaging layer slightly tacky. Thus, after exposure, when the receiver sheet is stripped from the imaging material, portions of the imaging material transfer to the receiver sheet in image configuration while the remainder is retained on the substrate so that a positive image is produced on one while a negative image is produced on the other. The body of the imaging layer may be at ambient temperatures structurally strong thus capable of withstanding shipping and storage. Only when activated by the application of heat does the layer become structurally cohesively weak and capable of fracturing to form an image.

The manifold set may include separate electrodes on opposite sides of the donor substrate and receiver sheet for the application of the field or the electrodes may be directly on the back surface of these members and integral therewith. In another field application technique, one or both of the substrate and receiver sheet may be made of a conductive material. The set may also be precharged with roller electrodes after fusion but before light exposure.

.The photoresponsive layer serves the dual function of imparting light sensitivity to the system while at the same time acting as a colorant for the final image produced, although other colorants such as dyes and pigments may be added to so as to intensify or modify the color of the final images produced when image color is important. The photoresponsive layer may be homogeneous or heterogeneous; that is may include one material dispersed throughout a second material. In addition, the photoresponsive layer, the activating layer or either electrode may have spectral or electrical sensitizers added thereto as desired.

In order that the invention will be more clearly under stood, reference is now made to the accompanying drawings in which an embodiment of the invention is illustrated by way of example, and in which:

FIG. 1 is a side sectional view of a first embodiment of a photosensitive imaging member for use in the imaging process of the invention;

FIG. 2 shows a schematic representation of the exnosure of the imaging member to an image to be produced;

3 and FIG. 3 schematically shows the step of developing the image formed by separating the donor and the receiver sheets.

'Referring now to FIG. 1 of the drawings, there is seen a supporting donor substrate layer 11 and an imaging layer generally designated 10. Superimposed on imaging layer is a receiving sheet 13. Imaging layer 10 is made up of photoresponsive layer 12 coated on donor substrate 11 and activating layer 14 coated on a photoresponsive layer 12. This combination of donor substrate layer 11, imaging layer 12 and receiving sheet 13 is referred to as a manifold set. Layer 12 is coated on substrate 11 so that it adheres thereto. Receiving sheet 13 is in contact with imaging activating layer 14 but does not adhere strongly thereto. At ambient temperatures, imaging layer 10 is sufliciently cohesively strong as to permit reasonable handling, shipping and storage. However, layer 10 is capable of being rendered cohesively weak upon heating. In the particular illustrative examples shown in FIG. 1, photoresponsive layer 12 consists of photoconductive pigment particles dispersed in a binder. This two-phase system has been found to constitute a preferred form for photoresponsive layer 12 in that it gives images of good resolution and is highly photosensitive. However, homogeneous layers made up, for example, of a single component or a solid solution of two or more components may be employed where these materials exhibit the desired photoresponse and have the desired physical properties. Since photoresponsive layer 12 serves as a photoresponsive element of the system as well as the colorant in the final image produced, the components of this layer are in most cases preferably selected so as to have a high level of photosensitivity while, at the same time, being intensely colored so that a high contrast image can be formed by the process of the invention. However, since the binder itself can be dyed or pigmented with additional colorant in either the single phase or two phase system, intense coloration of the photosensitive material itself, while being preferred, is not essential. Accordingly, the photosenstive material may be of any color, even transparent.

Any suitable photosensitive material may be employed in the imaging system of this invention with the selection depending largely upon the photosensitivity required, the spectral sensitivity desired, the degree of contrast desired in the final image, the color of the final image preferred, whether a heterogeneous or a homogeneous system is desired and similar considerations. Typical photosensitive materials include substituted and unsubstituted phthalocyanine; quinacridones; zinc oxide; mercuric sulfide; Algol Yellow (OJ. No. 67,300); cadium sulfide; cadmium selenide; Indofast brilliant scarlet (Cl. No. 71,140); zinc sulfide; selenium; antimony sulfide; mercuric oxide; indium trisulfide; titanium dioxide; arsenic sulfide; Pb O gallium triselenide; zinc cadmium sulfide; lead iodide; lead selenide; lead sulfide; lead telluride; lead chromate; gallium telluride; mercuric selenide; and the iodides; sulfides; selenides and tellurides of bismuth, aluminum and molybdenum. Also, organic photoconductors (including those complexed with small amounts, up to about 5%, of suitable Lewis acids) such as:

4,5-diphenylimidazolidinone;

4,5 -diphenylimidazolidinethinone;

4,5-bis-(4'-amino-phenyl)-imidazolidinone;

1,5 -cyano-naphthalene;

1,4-dicyanonaphthalene;

aminophthalodinitrile nitrophthalidinitrile;

1,2,5,6-tetraazacyclooctatetranene-(2,4,6,8)

3,4-di- (4'-methoxy-phenyl)-7,8-di-pheny1-l,2,5 ,6-

tetraazacyclooctatetraene- (2,4,6,8)

3,4-di- (4-phenoxy-phenyl-7,8-diphenyll ,2, 5,6-tetraazacyclooctatetraene- 2,4,6,8)

3,4,7 ,8-tetramethoxy-1,2,5 ,6-tetraazacyclooctatetraene- 2-mercaptobenzthiazole 2-phenyl-4-diphenylidene-oxazolone;

2-phenyl-4-p-methoxy-benzylidene-oxazolone;

6-hydroxy-2-phenyl-3- (p-dimethylamino phenyl) benzofurane;

6-hydroxy-2,3-di- (pmethoxyphenyl) -benzofurane;

2, 3 ,5 ,6-tetrap-methoxyphenyl -furo- 3 ,2f -benzofurane;

4-dimethylamino-benzylidene-benzhydrazide;

4-dimethylaminobenzylideneisonicotinic acid hydrazide;

Furfurylidene- (2) -4'-dimethylamino-benzhydrazide;

5-benzilidene-aminoacenaphthene;

3 -benzylidene-amino-carbazole;

( 4-N,N-dimethylamino-benzylidene -p-N,N-dimethylaminoaniline;

(2-nitrobenzylidene -p-bromo-aniline;

N,N-dimethyl-N'- 2-nitro-4-cyanobenzylidene p-phenylene-diamine;

2,4-diphenyl-quinazoline;

2- 4'-amino-phenyl -4-phenyl-quinazoline;

2-phenyl-4- (4'-di-methylamino-phenyl -7-methoxyquinazoline;

1,3-diphenyl-tetrahydroimidazole;

1,3-di- (4'-chlorophenyl -tetrahydroimidazole;

1,3-di-phenyl-2,4'-dimethyl amino phenyl) -tetrahydroimidazole;

1,3-di- (p-tolyl -2- [quinolyl-(2'-) ]-tetrahydroimidazole;

3- (4'-dimethylamino-phenyl -5- (4-methoxyphenyl- 6-phenyl-1,2,4-triazine;

3-pyridil- 4 -5- 4"-dimethyl-amino-phenyl -6-phenyl- 1,2,4-triazine;

3, (4'-amino-phenyl -S,6-di-phenyl-1 ,2,4-triazine;

2,5 -bis [4'-amino-phenyl-( 1') -1 ,3 ,4-triazole;

2,5-bis [4'- N-ethyl-N-acetyl-amino -amino-phenyl- (1') ]-l,3,4-triazole;

1,5 -diphenyl-3 -metl1yl-pyrazoline;

1,3 ,4,S-tetraphenyl-pyrazoline 1-methyl-2- 3 ',4'-di-hydroxymethylene-phenyl -bcnzimidazole;

2- (4'-di-methylaminophenyl -benzoxazole;

2- (4'-methoxyphenyl) -benzthiazole;

2,5-bis- [p-aminophenyl-( 1) ]-1,3,4-oxidazole;

4,5 -diphenylimidazolone;

B-aminocarbazole;

copolymers and mixtures thereof.

Any suitable Lewis acid (electron acceptor) may be employed under complexing conditions with many of the aforementioned more soluble organic materials and also with many of the more insoluble organics to impart very important increases in photosensitivity to those materials. Typical Lewis acids are 2,4,7-trinitro-9'-fluorenone; 2,4, 5,7-tetranitro-9-fluorenone; picric acid; 1,3,5-trinitrobenzene chloranil; benzoquinone; 2,5-dichlorobenzoqui none; 2-6-dichl0robenzoquinone; chloranil; naphthoquinone-( 1,4); 2,3-di-chloronaphthoquinone-(1,4); anthraquinone; Z-methyl-anthraquinone; 1,4-dimethyl-anthraquinone; l-chloroanthraquinone; anthraquinone 2 carboxylic acid; 1,S-dichloroanthraquinone, 1-chloro-4-nitroanthraquinone; phenanthrene-quinone; acenaphthenequinone; pyranthrenequinone; chrysene-quinone; thio-naphthenequinone; anthraquinone-1,8-disulfonic acid and anthraquinone-Z-aldehyde triphthaloylbenzene aldehydes such as bromal, 4-nitrobenzaldehyde; 2,6-di-chloro-benzaldehyde-2, ethoxy-l-naphthaldehyde; anthracene-9-aldehyde; pyrene-3-aldehyde; oxindole-3-aldehyde; pyridine- 2,6-dialdehyde, biphenyl-4-aldehyde; organic phosphonic acids such as 4-chloro-3-nitrobenzene-phosphonic acid; nitrophenols; such as 4-nitrophenol and picric acid; acid anhydrides; for example, acetic-anhydride, succinio anhydride, maleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride; perylene 3,4,9,l0-tetracarboxylic acid and chrysens-2,3,8,9-tetra-carboxylic anhydride; di-bromo maleic acid anhydride; metal-halides of the metals and metalloids of the Groups I-B, II through Group VIII of the periodical system, for example: aluminum chloride, zinc chloride, ferric chloride, tin tetrachloride, (stannic chloride); arsenic trichloride; stannous chloride; antimony pentachloride, magnesium chloride, magnesium bromide, calcium bromide, calcium iodide, strontium bromide, chromic bromide, manganous chloride, cobaltous chloride, cobaltic chloride, cupric bromide, ceric chloride, thorium chloride; arsenic tri-iodide; boron halide compounds, for example: boron trifluoride and boron trichloride; and ketones, such as acetophenone benzophenone; 2-acetylnaphthalene; benzil; benzoin; S-benzoylacenaphthene, biacenedione, 9-acetylanthracene, 9-benzoylanthracene; 4(4-dimethylamino-cinnamoyl) 1 acetylbenzene; acetoacetic acid anilide; indandione-(1,3)-(1-3- diketo-hydrindene); acenaphthene quinone-dichloride; anisil, 2,2-pyridil; furil; mineral acids such as the hydrogen halides, sulphuric acid and phosphoric acid; organic carboxylic acids; such as acetic acid and the substitution products thereof; monochloro-acetic acid; dichloroacetic acid; trichloro-acetic acid; phenylacetic acid; and 6-meth yl-coumarinylacetic acid (4); maleic acid, cinnamic acid; benzoic acid; 1 (4 diethyl-amino-benzoyl)-benzene- 2-carboxylic acid; phthalic acid; and tetrachlorophthalic acid; alpha-beta-dibromo-beta-formyl-acrylic acid (mucobromic acid); dibromo maleic acid; 2-bromo-benzoic acid; gallic acid; 3-nitro-2-hydroxyl-l-benzoic acid; Z-nitro phenoxy-acetic acid, 2-nitro-benzoic acid; 3-nitrobenzoic acid; 4-nitro-benzoic acid; 3-nitro-4-ethoxybenzoic acid; 2-chloro-4-nitro-l-benzoic acid, 2-chloro-4- nitro-l-benzoic acid, 3-nitro-4-methoxy-benzoic acid, 4-nitro-1-methyl-benzoic acid; 2-ch1oro-5-nitro-l-benzoic acid; 3-ch1oro-6-nitro-l-benzoic acid; 4-chloro-3-nitrol-benzoic acid; 5-chloro-3-nitro-2-hydroxy-benzoic acid; 4-chloro-2-hydroxy-benzoic acid; 2,4-dinitro 1 benzoic acid; 2-bromo-5-nitro-benzoic acid; 4-chlorophenyl-acetic acid; 2-chloro-cinnamic acid; Z-cyano-cinnamic acid; 2,4-dichlorobenzoic acid; 3,5-dinitro-benzoic acid; 3,5- dim'tro-salycylic acid; malonic acid; mucic acid; acetosalycylic acid; benzilic acid; butane-tetra-carboxylic acid; citric acid; cyano-acetic acid; cyclo-hexane-dicarboxylic acid; cyclo-hexane-carboxylic acid; 9,10-dichloro-stearic acid; furnaric acid; itaconic acid; levulinic acid; (levulic acid); malic acid; succinic acid; alpha-bromo-stearic acid; citraconic acid; dibromosuccinic acid; pyrene-2,3,7,8 tetra-carboxylic acid; tartaric acid; organic sulphonic acid, such as 4-toluene sulphonic acid; and benzene sulphonic acid; 2,4-dinitro-1-methyl-benzene-6-sulphonic acid; 2,6- dinitro-1-hydroxy-benzene-4-sulphonic acid and mixtures thereof.

In addition other photoconductors may be formed by complexing one or more suitable Lewis acids with aromatic polymers which are ordinarily not thought of as photoconductors. Typical aromatic polymers include the following illustrative materials; polyamides; polyimldes, polycarbonates, epoxy resins, phenoxy resins, aromatic silicone resins, polyphenylene oxide, polysulfones, melamine resins, phenolic resins, and mixtures and copolymers thereof where applicable. I

Phthalocyanines are preferred because of their h gh sensitivity and excellent color. Any suitable phthalocyanine may be used to prepare the photoconductive layer of the present invention. The phthalocyanine used may be in any suitable crystal form. It may be substituted or unsubstituted both in the ring and straight chain portions. Reference is made to a book entitled Phthalocyanine Compounds by F. H. Moser and A. L. Thomas, published by the Reinhold Publishing Company, 1963 edition for a detailed description of phthalocyanines and their synthesis. Any suitable phthalocyanine may be used in the present invention. Phthalocyanines encompassed within this invention may be described as compositions having four isoindole groups linked by four nitrogen at o r n s in such a manner so as to form a conjugated chain, said compositions having the general formula (C H N ).,R, wherein R is selected from the group consisting of hydro- 6 gen, deuterium, lithium, sodium, potassium, copper, silver, beryllium, magnesium, calcium, zinc, cadmium barium, mercury, aluminum, gallium, indium, lanthanum, neodymium, samarium, europium, gadolinium, dypsprosium, holmium, erbium, thulium, ytterbium, lutecium, titanium, tin, hafnium, lead, silicon, gervanium, thorium, vanadium, antimony, chromium, molybdenum, uranium, manganese, iron, cobalt, nickel, rhodium, palladium, osmium, and platinum; and n is a value of greater than 0 and equal to or less than 2. Any other suitable phthalocyanines such as ring or aliphatically substituted metallic and/or nonmetallic phthalocyanines may also be used if suitable. Typical phthalocyanines are: aluminum phthalocyanine, aluminum polychlorophthalocyanine, antimony phthalocyanine, barium phthalocyanine, beryllium phthalocyanine, cadmium hexadecachloro phthalocyanine, cadmium phthalocyanine, calcium phthalocyanine, cerium phthalocyanine, chromium phthalocyanine, cobalt phthalocyanine, cobalt chlorophthalocyanine, copper 4- aminophthalocyanine, copper bromochlorophthalocyanine, copper 4-chlorophthalocyanine, copper 4-nitrophthalocyanine, copper phthalocyanine, cooper phthalocyanine sulfonate, copper polychlorophthalocyanine, deuteriophthalocyanine, dysprosium phthalocyanine, erbium phthalocyanine, europium phthalocyanine, gadolinium phthalocyanine, gallium phthalocyanine, germanium phthalocyanine, hafnium phthalocyanine, halogen substituted phthalocyanine, holmium phthalocyanine, indium phthalocyanine, iron phthalocyanine, iron polyhalophthalocyanine, lanthanum phthalocyanine, lead phthalocyanine, lead polychlorophthalocyanine, cobalt hexaphenylphthalocyanine, copper pentaphenylphthalocyanine, lithium phthalocyanine, leutecium phthalocyanine, magnesium phthalocyanine, manganese phthalocyanine, mercury phthalocyanine, molybdenum phthalocyanine, naphthalocyanine, neodymium phethlocyanine, nickel phthalocyanine, nickel polyhalophthalocyanine, osmium phthalocyanine, palladium phthalocyanine, palladium chlorophthalocyanine, alkoxyphthalocyanine, alkylaminophthalocyanine, alkylmercaptophthalocyanine, aralkylaminophthalocyanine, aryloxyphthalocyanine, arylmercaptophthalocyanine, copper phthalocyanine piperidine, cycloalkylaminophthalocyanine, dialkylaminophthalocyanine, diaralkylaminophthalocyanine, dicycloalkylaminophthalocyanine, hexadecahydrophthalocyanine, imidomethylphthalocyanine, 1,2 naphthalocyanine, 2,3 naphthalocyanine, octaazaphthalocyanine, sulfur phthalocyanine, tetra-azaphthalocyanine, tetra 4 acetylaminophthalocyanine, tetra 4 aminobenzoylphthalocyanine, tetra 4 aminophthalocyanine, tetrachloromethylphthalocyanine, tetradiazophthalocyanine, tetra- 4,4 dimethyloctaazaphthalocyanine, tetra 4,5 diphenylene dioxide phthalocyanine, tetra-4,5 -diphenyloctaazaphthalocyanine, tetra (6 methylbenzothiazoyl) phthalocyanine, tetra p methylphenyl aminophthalocyanine, tetramethylphthalocyanine, tetra naphthotriazolylphthalocyanine, tetra 4 naphthylphthalocyanine, tetra 4 nitrophthalocyanine, tetra peri naphthylene 4,5 acta azaphthalocyanine, tetra 2,3-phenyleneoxide phthalocyanine, tetra 4 phenyloctaazaphthalocyanine, tetraphenylphthalocyanine, tetraphenylphthalocyanine tetracarboxylic acid, tetraphenylphthalocyanine tetrabarium carboxylate, tetraphenylphthalocyanine tetracalcium carboxylate, tetrapyridyphthalocyanine, tetra-4- trifluoromethylmercaptophthalocyanine, tetra 4-trifluoromethylphthalocyanine, 4,5 thionaphthene octaazaphthalocyanine, platinum phthalocyanine, potassium phthalocyanine, rhodium phthalocyanine, samarium phthalocyanine, silver phthalocyanine, silicone phthalocyanine, sodium phthalocyanine, sulfonated phthalocyanine, thorium phthalocyanine, thulium phthalocyanine, tin chlorophthalocyanine, tin phthalocyanine, titanium phthalocyanine, uranium phthalocyanine, vanadium phthalocyanine, ytterbium phthalocyanine, zinc chlorophthalocyanine, zinc phthalocyanine, others described in the Moser text and 7 mixtures, dimers, trimers, oligomers, polymers, copolymers or mixtures thereof.

It is also to be understood in connection with the heterogeneous system, that the photoconductive particles themselves may consist of any suitable one or more of the aforementioned photoconductors, either organic or inorganic, dispersed in, in solid solution in, or copolymerized with, any suitable insulating resin Whether or not the resin itself is photoconductive. This particular type of particle may be particularly desirable to facilitate dispersion of the particle, to prevent undesirable reactions between the binder and the photoconductor or between the photoconductor and the activator and for similar purposes. Typical resins include polyethylene, polypropylene, polybutylene, polyamides, polymethacrylates, polyacrylates, polyvinyl chlorides, polyvinyl acetates, polystyrene, polysiloxanes, chlorinated rubbers, polyacrylonitrile, epoxies, phenolics, hydrocarbon resins and other natural resins such as rosin derivatives as well as mixtures and copolymers thereof. Polyethylene is preferred because of its low melting point and because it is readily available.

The binder material in the heterogeneous imaging layer may comprise any suitable cohesively weak insulating or photoconductive insulating materials. Typical cohesively weak materials include the insulating resins listed above particularly the lower molecular weight polyethylenes, polybutylenes and polypropylenes; vinyl acetate-ethylene copolymer; styrene-vinyl toluene copolymers; microcrystalline wax; parafiin wax; other low molecular weight polymers and copolymers and mixtures thereof.

A mixture of microcrystalline and paraflinic waxes is preferred because it is cohesively weak and a good insulator.

In the heterogeneous system, the ratio of photoconductor to binder in photoresponsive layer 12 may range from about 10:1 to about 1:10 (by volume), but is has generally been found that proportions in the range from about 1:2 to about 2:1 produce the best results and, accordingly, this constitutes a preferred range.

The electrodes may consist of any suitable conductive material. Typical conductive electrode materials include aluminum, brass, stainless steel, copper, nickel, zinc and mixtures thereof. Aluminum is preferred because it is readily available and because it is a good conductor.

The donor substrate and the receiving sheet may consist of any suitable insulating material. Typical insulating materials include polyethylene, polyethylene terephthalate, cellulose acetate, paper, plastic coated paper, such as polyethylene coated paper, and mixtures thereof. Mylar, a polyester formed by the condensation reaction between ethylene glycol and terephthalic acid available from the E. I. du Pont de Nemours & Company, Inc. is preferred because of its physical strength and because it has good insulation qualities. Alternatively, the receiving sheet may be conductive, such as aluminum foil or an aluminum coated insulating film.

Activating layer 14 has a lower melting temperature than does photoresponsive layer 12. Activating layer 14 may be homogeneous or heterogeneous; that is, may include an activating material dispersed in a binder. During assembly of the manifold set, activating layer 14 may beformed initially either on the surface of photoresponsive layer 12 or on the surface of receiving sheet 13. Activating layer 14 may comprise a material such as a low melting wax which melts at a lower temperature than layer 12, rendering layer 12 cohesively weak and the layer 12-sheet 13 interface tacky. Alternatively, activating layer 14 may comprise, alone or in a binder a thermosolvent. A thermo-solvent is an ingredient which is solid at ordinary room temperatures but which melts slightly above room temperature. When melted, this material is a solvent for the binder material used in photoresponsive layer 12. By partially dissolving binder material, photoresponsive layer 12 is rendered cohesively weak and at least somewhat tacky and is capable of 8 cleaving sharply along the edges of images to be formed therefrom. Preferred thermo-solvents and low melting waxes include materials which are solid at room temperature but melt at temperatures below F. Especially good results have been obtained with long chain petroleum waxes with from about 18 to about 30 carbon atoms in the chain. Typical low melting waxes include octadecane, nonadecane, eicosane, hene-icosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane, nonacosane, triacontane, and mixtures thereof. If desired, these low melting waxes may be mixed with other materials, such as higher melting waxes. Typical thermo-solvents which may be dispersed in a binder or used alone where suitable include m-terphenyl, Aroclar 5442 (a chlorinated polyphenyl, melting point 46-52 C. from Monsanto Chemical Company), perchloro hydrocarbons, polybutylenes, biphenyl, and mix tures thereof. Typical binder materials suitable for. use with some thermo-solvents include the low melting Waxes described above and the donor-layer binders listed above.

After imaging, separation of receiving sheet 13 from donor substrate 11 and cooling of the material to room temperature, the thermo-solvent will resolidify. This will tend to fix images produced since the resin is now in a tougher, more abrasion resistant form. The images formed will be more easily handled and more resistant to abrasive damage than would be the case where imaging layer 10 was cohesively weak at room temperatures.

FIG. 2 shows a typical embodiment of a means for exposing the manifold set to a light-and-shadow image. The exposure means here consist of a lamp 15, a transparency 16 and a lens 17. During exposure, a potential is applied across imaging layer 12. In this instance, donor substrate layer 11 is transparent and conductive, e.g., tin oxide coated glass. Receiving sheet 13 is also conductive so that the potential is applied by a means of power supply 18 connected to the donor substrate and receiving sheet through resistor 19. Preferred field strengths are in the range of about 1000 to 2000 volts per mil across the manifold set. Thus, the applied voltage will ordinarily be in the range of 4000 to 10,000 volts. To prevent air gap breakdown when the receiving sheet is stripped from the donor substrate, a fairly large resistor is preferably inserted in series with the power supply to limit the flow of current and the rate of charging of the capacitor which the manifold set forms. A fairly large resistor on the order of from about at least 5000 to 20,000 mg./ ohms satisfactorily performs this function. During exposure, the manifold set is heated by means of heated platen 20 to such a temperature that the layer 12 will be cohesively weak when receiving sheet 13 is stripped from the manifold set. Where a thermo-solvent is used, this temperature will be slightly above the melting point of the thermo-solvent. Alternatively, the manifold set may be heated just before imaging so long as the imaging layer 10 remains in a cohesively weak state during imaging or until receiving sheet 13 is stripped from the manifold set to develop the image. Also, the heating could take place after exposure to the image and either before or during separation of the receiving sheet 13 from the manifold set.

FIG. 3 shows schematically the development of the visible image. While the potential is maintained across the manifold set, and while imaging layer 10 remains c0- hesively weak, receiving sheet 13 is stripped from the manifold set. Generally, a positive image is formed on the donor substrate and a negative image on the receiving sheet. Thus, portions of layer 12 which were light struck transfer to receiving sheet 13 while non-light struck portions remain on donor sheet 11. During this development operation, the imaging layer 10 remains in its heated, cohesively weak state. After separation, the imaged sheet 11 and 13 are cooled to room temperature. The portion of imaging layer 12 on each sheet thus returns to its cooled, structurally sturdy, state. Where desired, the images may be further fixed by any suitable method, such as overcoating with a resin or laminating a transparent sheet thereover.

The following examples further define and describe the invention with respect to improved imaging methods. Parts and percentages are by weight unless otherwise indicated. The examples below should be considered to illustrate various preferred embodiments of the invention.

EXAMPLE I About parts of Sunoco 1290, a microcrystalline wax with a melting point of about 178 F. available from the Sun Oil Company, is dissolved in about 100 parts of reagent grade petroleum ether. To this solution is added about 5 parts of finely divided x-form metal-free phthalocyanine produced by the process described in copending application Ser. No. 505,723, filed Oct. 29, 1965. This paste is then placed in a ball mill jar with clean porcelain balls. The formulation is then ball milled for about 3 /2 hours at about 70 r.p.m. After milling, about 20 parts of Sohio Odorless Solvent 3440, a kerosene fraction available from Standard Oil of Ohio, is added to the paste. This paste is then coated onto a 2 mil Mylar (polyethylene terephthalate, available from E. I. du Pont de Nemours & Company) donor sheet with a No. 36 wire-wound rod which produces a coating thickness of about 7 /2 microns after drying. A mixture of about 2.5 parts eicosane (technical grade, a mixture of predominately straight chain hydrocarbons averaging 20 carbon atoms to the molecule) and about 7.5 parts Sunoco 5825, a petroleum wax available from the Sun Oil Company are suspended in about 100 parts Sohio Odorless Solvent 3440 and applied to a 2 mil Mylar receiving sheet. A No. 12 wire-wound draw down rod is used which produces a 2.5 micron thick coating on Mylar receiving sheet. The coated surface of the Mylar receiving sheet glass is then brought into surface contact with the phthalocyanine containing layer on the Mylar donor sheet. The donor side of the resulting manifold set is then placed against the conductive coating on a NESA glass plate. The ground terminal of the 10,000 volt DC. power supply is then connected to the NESA coating in series with a 5500 mg.-ohm resistor and the negative terminal is connected to the black opaque electrode. With the voltage applied, a white incandescent light image is projected through the NESA glass onto the photosensitive layer. Exposure is about 0.2 foot-candles for about two seconds. Simultaneous with the exposure, a 15 volt AC. power supply connected to the NESA coating is activated, heating the set to about 150 F. by resistance in the NESA coating. At this temperature, the thin layer of eicosane in Sunoco 5828 melts. After exposure, the receiver sheet is peeled from the set with the potential source still connected. The set is allowed to cool after exposure so that after separation of the sheets a pair of excellent quality images with a duplicate of the original on the donor sheet and a reversal of the original on the receiver sheet are produced.

EXAMPLES II-V The procedure of Example I is repeated for each of these examples except that in place of the 5 parts phthalocyanine, the following photosensitive materials are used: for Example II, about 6 parts Algol Yellow GC, C.I. No. 67300, 1,2,5,6-di (C,C'-diphenyl)-thiazole-anthraquinone, available from General Dye Stuffs; for Example III, about 6 parts Watchung Red B, C.I. No. 15865, 1-(4'-methyl- 5'-chloroazobenzene-2-suflonic acid)-2-hydroxy-3-naphthoic acid, available from E. I. duPont de Nemours & thoic acid, available from E. I. du Pont de Nemours & 8, 13 dioxodinaphtho-(1,2-2',3')-furan-6-carboxamide, prepared in copending application Ser. No. 421,281, filed Dec. 28, 1964; and for Example V, about 6 parts Monolite Fast Blue GS, the alpha form of metal-free phthalocyanine, available from Arnold Hoffman Company. In each case an excellent image conforming to the original results.

10 The image produced in Examples I and V are cyan in color, Examples 11 and IV produce yellow images and Example III a magenta image.

EXAMPLES VI-VHI The procedure of Example I is followed in each of these examples except that the following matereials are substituted for the Sunoco 1290 used in Example I: for Example VI, Sunoco 985, a microcrystalline wax having an ASTM-Dl27 melting temperature of 193 F. is used; for Example VII Sunoco 5512, a paraffin wax having a melting temperature of 153 F. (ASTM-D-87) is used; and for Example VIII Epolene C-12, a low molecular weight polyethylene having an approximate molecular Weight of 3,700, a ring and ball softening temperature of 92 C., an acid number of 0.05 and a density at 25 C. of 0.893 (available from the Eastman Chemical Products Company) is used. Each of these binders produces good images conforming to the original. Some background, observable as a blue haze, is observable in Example VII, apparently due to the relatively low melting temperature of the Sunoco 5512.

EXAMPLES IX-XII The procedure of Example I is followed, except that in these examples the eicosane-Sunoco 5825 heat activatable layer is replaced by other materials.

In Example IX this layer consists of about 5 parts docosane mixed with about 5 parts Sunoco 5825. This layer is coated directly over the phthalocyanine-Sunoco 1290 layer and a NESA glass plate is placed over the thus formed layer. The resulting manifold set is then imaged as in Example I, producing a good image conforming to the original.

In Example X, technical grade heptacosane is coated from a solution in ethanol onto the receiving sheet surface to a dry thickness of about 2 microns. The resulting manifold set is heated to about F. during imaging. An excellent image results.

In Example XI, a mixture of about 4 parts Aroclor 5442 and about 6 parts Sunoco 5512 is coated onto the receiving sheet surface as in Example I. The manifold set is heated to about F. during imaging. A good image corresponding to the original results.

'EXAMPLE XII The procedure of Example I is followed, except that the following layer is used in place of the phthalocyanine- Sunoco 1290 layer.

This layer is prepared as follows: about 8 parts 2,5- bis(p-aminophenyl)-l,3,4-oxadiazole and about 11 parts Lucite 2008, a low molecular Weight polymethylmethacrylate (from E. I. du Pont de Nemours & Company) are dissolved in about 70 parts methyl ethyl ketone. To this solution is added about 0.25 parts Rhodamine B [9-(O-carboxyphenyl)-6-(diethylamino) 3 xanthene- 3-xylene]-diethyl-chloride available from E. I. du Pont de Nemours & Company. This solution is then coated onto a 2 mil Mylar sheet and partially dried. Before the coating is fully dried, it is dipped into a methanol bath which dilutes the solution, causing the solids to precipitate out in a weak, semi-particulate form in which individual particles are bonded at their interface much like a sintered layer. The donor thus prepared is dried at about 50 C. and is used according to the procedure of Example I. An image of good quality, but of lower resolution than that in Example I results.

Although specific components and proportions have been stated in the above description of preferred embodiments of the manifold set used in the process of this invention, other suitable materials as listed above, may be used with similar results. In addition, other materials may be added to the various elements of the manifold set to synergize, enhance, or otherwise modify their properties. For example, colorants, spectral or electrical sensi- 1 1 tizers or conductivity modifying ingredients may be added to the donor substrate, imaging layer or receiving sheet Where desired.

Other modifications and ramifications of the present invention will occur to those skilled in the art upon a reading of the present disclosure. These are intended to be included within the scope of this invention.

What is claimed is:

1. An imaging method which comprises the steps of:

(a) providing a manifold set comprising an insulating donor substrate having coated thereon an imaging layer, comprising an electrically photosensitive material dispersed in an insulating binder, an activating layer comprising a thermo-solvent overlying said imaging layer, and a receiving sheet overlying said activating layer; said activating layer having a lower melting temperature than said imaging layer and is at least a partial solvent for said imaging layer when melted and at least one of said donor and receiver layers being at least partially transparent to light;

(b) activating said imaging layer by means of heating said manifold set to a temperature above the melting temperature of said activating layer but below the melting temperature of said imaging layer thereby rendering said imaging layer fracturable in response to an electric field and light to which said imaging layer is sensitive;

(c) exposing said imaging layer to a light pattern to which said imaging layer is sensitive while said imaging layer is subjected to an electric field; and

(d) while maintaining an electric potential across said manifold set, separating said receiving sheet from said donor substrate whereby said imaging layer fractures in imagewise configuration and the exposed portion thereof is retained on one of said donor substrate and receiving sheet while the unexposed portion is retained on the other.

2. The method of claim 1 wherein said imaging layer comprises a particulate photoresponsive material dispersed in a binder selected from the group consisting of photoconductive insulating and electrically insulating materials and said activating layer comprises a low melting wax.

3. The method of claim 1 wherein said activating layer 12 comprises a mixture of a binder selected from the group consisting of photoconductive insulating and electrically insulating materials and a thermo-solvent and said heating step is to a temperature above the melting temperature of said thermo-solvent.

4. The method of claim 1 in which said potential has strength ranging from about 1,000 to about 2,000 volts per mil across said set.

5. An imaging member comprising:

(a) an electrically insulating donor substrate;

(b) overlying said substrate an electrically photosensitive imaging layer;

(c) overlying said imaging layer an activating layer comprising a thermo-solvent having a melting temperature lower than said imaging layer; and

(d) a receiver layer overlying said activating layer; at least one of said donor and receiving layers being at least partially transparent to light to which said imaging layer is sensitive.

6. The imaging member of claim 1 in which said imaging layer comprises a particulate photosensitive material dispersed in a binder selected from the group consisting of photoconductive insulating and electrically insulating materials.

7. The imaging member of claim 5 in which said activating layer comprises a mixture of a thermo-solvent and a binder selected from the group consisting of photoconductive insulating and electrically insulating materials, the melting temperature of said thermo-solvent being lower than the melting temperature of said imaging layer.

References Cited UNITED STATES PATENTS 3,441,410 4/1969 Brynko 961X FOREIGN PATENTS 6,604,725 6/1966 Netherlands 96---1 GEORGE F. LESMES, Primary Examiner J. R. MILLER, Assistant Examiner U.S. Cl. X.R. 

